1. Field of the Invention
The present invention generally relates to a recording apparatus for printing, for example, a lottery ticket, a bar code label, other kinds of tickets or the like, and more particularly to a recording apparatus which uses thermosensitive (namely, heat-sensitive or thermographic) paper of the optical-fixing type, on which color-development is performed by heat and further, an image is optically fixed.
2. Description of the Related Art
In recent years, thermal recording apparatuses using thermosensitive paper as recording paper have come into wide use as a simplified output device for use in a facsimile system or the like owing to the simplicity thereof. Such a recording apparatus has a structure, wherein thermosensitive paper is conveyed onto a plurality of heating elements that are placed and spread in a direction perpendicular to the direction in which the thermosensitive paper is conveyed, and wherein arbitrary ones of the heating elements placed therein are selected and energized simultaneously with the conveyance of the thermosensitive paper, and the color recording of an image is then performed by utilizing heat produced by the energized ones of the heating elements.
Such conventional recording apparatuses, however, have drawbacks in that after the recording is once accomplished, an uncolored part may be colored by heat originated from sunlight or may be chemically colored owing to the depositing of alcohol or the like thereon, namely, in that a recorded image may be tampered or deteriorated and cannot be well preserved. The thermosensitive paper used in such conventional recording apparatuses are, therefore, unsuited to recording media which are required to have high reliability and are used for a lottery ticket, a bar code label, other kinds of tickets or the like.
Meanwhile, for the purpose of solving the problems of preventing the color-redevelopment (or re-coloring) of thermosensitive paper and improving the preservability thereof, thermosensitive paper of the optical fixing type has been proposed by Fuji Photo Film Co., Ltd., and has been developed into a product that has already been on the market. This thermosensitive paper has been announced or described in detail in a reference material for a seminar held on May 31, 1995, by Technology Information Association, which is entitled "Thermo-Autochrome Full Color Recording Technology".
There are two kinds of methods for recording an image on this thermosensitive paper of the optical fixing type. A first method is to first selectively perform the color-development of the thermosensitive paper by heat and thereafter perform the optical fixing of colored and uncolored parts thereof by utilizing ultraviolet light. A second method is to first perform the color-development of the thermosensitive paper by selectively emitting light and thereafter perform the fixing and color-development thereof by heat. The fact, however, is that these methods have encountered various problems as will be described hereinbelow, and thus do not come into wide use.
FIGS. 60 and 61 are sectional diagrams for illustrating a conventional recording apparatus that employs this first method. As shown in these figures, a thermal head 1 is provided in a housing (not shown) of the recording apparatus. Further, a plurality of heating elements 2 are provided on the thermal head 1 in such a way as to be arranged in a line. Furthermore, recording paper, which is thermosensitive paper of the optical fixing type, is placed on the heating elements 2. The heating elements 2 are arranged in a direction perpendicular to the direction in which the thermosensitive paper is conveyed.
Furthermore, a circuit component configuration portion 6, in which circuit components for driving the heating elements 2 are placed, is provided on the thermal head 1. Further, a platen roller 4 for conveying recording paper is placed by being supported by the housing (not shown) in such a manner as to be opposed to the heating elements 2. The platen roller 4 is operative to feed the recording paper 5 to the left as viewed in FIG. 60. Moreover, a lamp 3 is disposed in front of the thermal head 1 in the direction of conveyance of the recording paper 5 in parallel with the heating elements 2. The lamp 3 constitutes a light emitting means for fixing an image on the recording paper.
In the conventional recording apparatus having such a configuration, the recording paper 5 is fed by the platen roller 4 on the thermal head 1. Further, only parts, on which the recording of image data is performed by selectively driving arbitrary heating elements 2, of the recording paper 5 are colored by heat. Subsequently, when the recording paper 5 passes through the vicinity of the lamp 3, an image is fixed on the recording paper 5 by light emitted from the lamp 3.
The lamp 3 is driven at a high voltage of several hundreds volts and generates heat at a high temperature. Therefore, when the recording paper 5 approaches the lamp 3, the color-redevelopment occurs owing to the temperature of the lamp 3 before the optical fixing of an image is performed on the recording paper 5. In this case, the recording of the image is impossible. Thus, in the conventional recording apparatus, a predetermined spacing L between the lamp 3 and the recording paper 5 should be left or allowed so as to prevent the recording paper 5 from being colored owing to heat radiated from the lamp 3.
Further, FIG. 62 is a top view of the conventional recording apparatus that is in a state in which the platen roller 4 is removed therefrom. This figure illustrates the placement of the thermal head 1 and the lamp 3 in the recording apparatus. As illustrated in this figure, the lamp 3 has a width that is considerably wide in comparison with the width of the arrangement array or line of the heating elements 2 of the thermal head 1 and with the width of the recording paper 5. This is owing to the electrode structure of the lamp 3. Namely, the drive electrode terminals thereof are drawn from both edges of the lamp 3, respectively. Thus, the lamp 3 has a same structure as of a fluorescent lamp using an ordinary alternating-current power source.
FIG. 63 is a graph for illustrating the distribution of quantity of light (or the luminous energy distribution) of the lamp 3 of the conventional recording apparatus. As is seen from this figure, the quantity of light is low at each of the electrode portions of the lamp 3 and does not come up to the fixing quantity of light (namely, the quantity of light required for fixing or fixation). Therefore, if the apparatus is established in such a manner that the fixing quantity of light is obtained throughout the width of the recording paper 5, the lamp 3 should have a length longer than the width of the recording paper 5. Incidentally, in the case of the recording paper, whose width is equal to that of an A4 page, the width of the lamp 3 should be equal to that of an A3 page or so.
FIG. 64 is a diagram for illustrating operations of opening and closing the cover of another example of the conventional recording apparatus. Further, FIG. 65 is a diagram for illustrating the placement of components in this recording apparatus. As shown in these figures, a housing 120 of the recording apparatus consists of a chassis 122 and an open/close cover 121 attached to the chassis 122. The cover 121 is opened when changing the recording paper 5 enclosed in the housing 120, and when replacing a recording head 123.
In the housing 120, the recording paper 5 wound like a roll is enclosed and the thermal head 1 for recording an image on the recording paper 5 is placed. Further, the conveying platen roller 4 is placed in such a manner as to face the thermal head 1. The thermal head 1 is pushed by a spring 128 to the conveying platen roller 4.
Furthermore, an optical detection sensor 126 for detecting the recording paper 5, and another optical detection sensor 127 for detecting the opened and closed states of the cover 121 are placed in the housing 120.
In the case of the conventional recording apparatus having such a configuration, because of the necessity of the predetermined spacing L between the lamp 3 and the recording paper 5, the thermal head 1 and the lamp 3 are supported by different members (not shown), respectively. Further, the presence of the spacing L between the thermal head 1 and the lamp 3 sometimes causes the recording paper 5 to jam therebetween.
Meanwhile, for the purpose of realizing a mechanism by which a paperjam is hard to occur, there has been contrived a method of increasing the spacing L between the lamp 3 and the recording paper 5, as illustrated in FIG. 66. However, when increasing the spacing L, the lamp 3 goes away from the recording paper 5 this time. Thus, there is caused another problem that the quantity of light required to achieve the fixing cannot be obtained.
Additionally, when increasing the quantity of light emitted from the light source by raising a source voltage for driving the lamp 3, significant degradation in quantity of light due to the use of the lamp 3 is caused. Consequently, this results in occurrence of still another problem that the life of the lamp 3 is reduced.
This is owing to the electrode structure of the lamp 3, namely, to the fact that the drive electrode terminals are drawn from both edges of the lamp 3, respectively, and that the lamp 3 has a same structure as of a fluorescent lamp using an ordinary alternating-current power source.
Moreover, as above described, in the case of the conventional recording apparatus, the length of the lamp 3 should be larger than the width of the recording paper 5. This method, thus, has faced the problem that a reduction in size of the recording apparatus cannot be achieved.
Furthermore, an optical detection sensor 126 for detecting the recording paper 5, and another optical detection sensor 127 for detecting the opened and closed states of the cover 121 are placed in the housing 120. Thus, the number of components provided in the housing 120 is large. Further, the structure of the apparatus is complex.
Meanwhile, even when a recording operation is failure owing to a failure or defect of the heating elements 2, a sustain on the recording paper, oblique feeding of the recording paper, a break of the recording paper and so forth, there are no effective detecting means and thus no reliability of the recording cannot be obtained. The conventional recording apparatus, therefore, has a drawback in that record information output cards (or tickets), to which a record of money information concerning a lottery ticket, a bar code or other kinds of tickets is outputted, cannot be used because of the fact that there is no reliability of the record.
Furthermore, when failures or malfunctions of the heating elements 2 and the lamp 3 occur, such components provided in the recording apparatus cannot easily be replaced. Further, it is difficult for persons other than engineers (for example, a seller of lottery tickets and a station employee) to replace such a component. Thus, the conventional recording apparatus has a defect in that the maintenance thereof is difficult.
The present invention is accomplished to solve the problems (namely, eliminate the drawbacks) of the prior art.
It is, accordingly, an object of the present invention to provide a recording apparatus which can be miniaturized and can enhance the reliability thereof and can easily achieve the maintenance thereof.